1. Field of the Invention
This invention relates generally to the field of electric power circuit interrupter devices, and in particular to a combination vacuum interrupter and visible break disconnect switch.
2. Prior Art
In known combination vacuum interrupter and visible break disconnect switches, such as the vacuum loadbreak switch disclosed in U.S. Pat. No. 3,824,359 issued on July 16, 1970 to Kazuo H. Date, a vacuum interrupter, connected electrically in parallel with a visible break disconnect switch, has a quick break operating mechanism actuated by the disconnect switch, to trip the vacuum interrupter upon opening of the disconnect switch and thus interrupts the load current then flowing solely through the vacuum interrupter.
In such a compact combination interrupter and disconnect switch, it would be very advantageous if the vacuum interrupter were electrically connected in series with the disconnect and could be operated independently of the disconnect only when the disconnect were closed, and the disconnect could be operated independently of the vacuum interrupter only when the interrupter were open. In such an arrangement, the vacuum interrupter could be used to automatically interrupt fault currents or to trip under low voltage conditions. A combination switch of this type would be particularly advantageous in industries such as the mining industry, in which undervoltage protection and padlockable, visible break disconnects are generally required, and compact sized equipment is highly desirable because of space limitations.